A core engine of a gas turbine engine typically includes a multistage compressor which provides compressed air to a combustor wherein it is mixed with fuel and ignited for generating hot combustion gas which flows downstream through a high pressure turbine nozzle, and in turn through one or more stages of turbine rotor blades. The high pressure turbine blades are joined to a rotor disk which is joined to the compressor by a corresponding drive shaft, with the turbine blades extracting energy for powering the compressor during operation. In a two spool engine, a second shaft joins a fan upstream of the compressor to a low pressure turbine disposed downstream from the high pressure turbine.
In one known configuration, the turbine includes doublet vane segments that that are attached to each other at circumferentially spaced edges. Each segment typically includes an outer vane platform segment, an inner vane platform segment, and a pair of vanes extending radially between the inner and outer vane platform segments. The vanes comprise airfoils that are subjected to cooling air flow.
In one known engine configuration, airfoil cooling air is utilized to cool the platform before sending the air into the airfoils. Space-eater baffles and coverplates are used to create channels through which the air flows. In this configuration, the cooling air is required to enter at a certain location and must maintain a relatively constant channel height in order to provide the necessary cooling. However, when radial and circumferential core shifts and tolerances are taken into account, using conventional baffles and coverplates could either result in large fluctuations in channel heights or cause leakage gaps to open up. This reduces cooling effectiveness in the platform region.